No. 9 double-window envelopes with full-size, gummed flaps are designed for most standard 8-1/2" x 11" computer-generated invoices and statements. Poly windows and inside tint provide security. The 1-3/16" x 3-1/2" top window is positioned 3/8" from the left and 2" from the bottom. The 1" x 4" bottom window is positioned 3/8" from the left and 1/2" from the bottom. White wove envelopes are made of 24 lb. stock. Envelopes come in a bulk shipping container to reuse as a letter-size file box for home or business use.